top cover for tomatos

Sjmillman · Fri Mar 21, 2014 4:49 pm

I am growing heirloom tomatos in large pots this year. Does anyone know if it is ok to use sphagnum peat moss as a top cover to retain water in the pots? Is it too acidic?

Juliuskitty · Fri Mar 21, 2014 5:52 pm

Peat moss is acidic. A better top cover suggestion might be a white trash bag cut open, then stretched over the pot and clipped onto the edges,or tied on with rope, then cut a hole in the cover and plant your tomato. You will be able to water at the base, or if you have a self watering pot, just cut a hoe a little small and stretch it over the PVC watering pipe. If your tomato is already in the pot just cut the cover to go around it, and close the radial cut by holding it together with binder clips. The plastic will keep water in and critters out, and keep the soil from splashing onto the tomato when watered.
This isn't the only way, but it is one way that is easy and works.

rainbowgardener · Sat Mar 22, 2014 8:16 am

"top cover" like that is usually called mulch. If your tomato plants are in potting soil, it is probably mainly peat moss anyway, a little more might not hurt it. But it does have a pH down around 4.5 and no nutrients. So something with a more neutral pH, that would add some nutrients as it breaks down would make a better mulch for your tomato containers. Regular compost, grass clippings, bark mulch, fall leaves....

I wouldn't expect that soil splash causing disease would be much of an issue with container grown tomatoes, but it is possible if you re use potting soil from last year.

Bobberman · Sat Mar 22, 2014 10:22 pm

Put something in the bottom of the container to hold a few inches of water at the bottom so when you water all the water does not run out! I would put some small white gravel at the top to reflect the light and keep the moisture under the gravel. The gravel would also keep the soil cooler on hot days. You can buy a bag of white gravel cheap!

Some people run a small plastic pipe to the bottom of the water holder and water from the bottom and top! If you large container has no hole in the bottom drill a hole 2 to 3 inches up from the bottom so the container holds some water at the bottom! When you see the water run out you know you have watered enough!

rainbowgardener · Sun Mar 23, 2014 6:56 am

Wow... sorry, but I really disagree. Keeping water in the bottom of your container sounds like a really bad idea to me. You do not want your soil to stay wet all the time. I think bobber is talking about trying to make a homemade self-watering container. But in self watering containers, the soil is NOT in contact with the water beneath, they are separated, with just a wick connecting the soil to the water underlying. Or in some cases nothing connecting them, but some pores in the barrier between so water vapor can rise in to the soil.

Even so I don't really like growing in self watering containers, because it seems difficult to manage the soil moisture that way. A lot of things like to dry out a bit between waterings, but the swc doesn't allow that to happen. Just water your containers when they need it; not that hard.

I haven't tried the gravel mulch, but 1) it doesn't break down to feed the soil and 2) it seems like even white gravel sitting in the sun would tend to heat up.

Bobberman · Sun Mar 23, 2014 11:21 am

Brown peat gets much warmer in the sun than white gravel or anything white! White reflects light back to the under part of the tomato. When you use gravel because it has many angled surfaces the light is bounced in all directions and makes a great reflective surface. Roots from tomatoes can grow to the bottom of any container even if its 18 inches deep and will benefit from a water source at the bottom! That is my opinion and I have tried it with success! Perlite covered with white gravel also works because the gravel stops the perlite from blowing away ! Also white plastic with holes under the white gravel works. There are all kinds of toppings that will work! Black absorbs white reflects! Dark in spring white in summer!

Juliuskitty · Sun Mar 23, 2014 1:18 pm

Bobberman wrote:Brown peat gets much warmer in the sun than white gravel or anything white! White reflects light back to the under part of the tomato. When you use gravel because it has many angled surfaces the light is bounced in all directions and makes a great reflective surface. Roots from tomatoes can grow to the bottom of any container even if its 18 inches deep and will benefit from a water source at the bottom! That is my opinion and I have tried it with success! Perlite covered with white gravel also works because the gravel stops the perlite from blowing away ! Also white plastic with holes under the white gravel works. There are all kinds of toppings that will work! Black absorbs white reflects! Dark in spring white in summer!

+1
I agree with this entire post!

Bobberman · Sun Mar 23, 2014 2:43 pm

Another thing worth mentioning is all types of peat even peat pots act like a wick and will dry out very fast especially if there is a slight wind. Peat pots to me are bad unless watered from the bottom! Peat is pushed by stores and seed companies as opposed to Styrofoam cups because you can by the Styrofoam cups anywhere for a penny each and there is no profit to seed companies or any garden sales program. To me styrofoam cups are the best for seed starting and there could me more applications if you do not consider them a danger! I buy 20 ounce Styrofoam cups for my cold drinks and use them year around with ice and tea!